I would like to see them come back. It would be nice to have higher limits on the numbers of players ( 8, 16, 32, 64, 128 ) to allow host user to decide.
I think that the community can build their own maps a lot quicker and with a lot more diversity than what we have now. There were a lot more play options available with all of the various custom rooms in 8 player. As it is now, the stock rooms are just quite boring to me. Yea, they update them a little with every new version. But over all, they look pretty much the same, not much to choose from.